Will this fix my internet problem?

For the past week I've been having internet issues where my internet will kind of "reset". It disconnects me from everything, then randomly reconnects. And for about 30 seconds after these resets, I have no connection whatsoever. One night however this black out period lasted several hours. Charter sent out a tech to take a look at the wiring and he said everything seemed fine, and that the connection issues should go away. However today, about 5 days after the tech came, the issues came back. I'll be playing my games and the internet will randomly go out. I already tried getting a new USB wifi adapter, resetting my router, etc and nothing helps. So I called up Charter and they told me I should buy an "amplifier" that should fix the problem. I didn't really get the chance to say no, he just said "let me put you on hold" then when he came back he asked what time would be best for the tech to come out and install it.
Before I call back and cancel, I'd like to know if this will actually help of if they're just trying to milk me for extra money?

On another note, I've noticed the issue is happening when it's most cold outside. Right now it's about 9 degrees F. Could the temperature have an adverse effect on my wifi?

For the past week I've been having internet issues where my internet will kind of "reset". It disconnects me from everything, then randomly reconnects. And for about 30 seconds after these resets, I have no connection whatsoever. One night however this black out period lasted several hours. Charter sent out a tech to take a look at the wiring and he said everything seemed fine, and that the connection issues should go away. However today, about 5 days after the tech came, the issues came back. I'll be playing my games and the internet will randomly go out. I already tried getting a new USB wifi adapter, resetting my router, etc and nothing helps. So I called up Charter and they told me I should buy an "amplifier" that should fix the problem. I didn't really get the chance to say no, he just said "let me put you on hold" then when he came back he asked what time would be best for the tech to come out and install it.
Before I call back and cancel, I'd like to know if this will actually help of if they're just trying to milk me for extra money?

On another note, I've noticed the issue is happening when it's most cold outside. Right now it's about 9 degrees F. Could the temperature have an adverse effect on my wifi?

Temperature should have no affect on your WiFi signal. Is wireless your only option for internet connectivity? The only weather effects that should affect your Wifi signal is heavy rain, snow, or lightning storms. Water is going to absorb some of the radio signal and large amounts of it in the air from rain or snow will reduce the strength.

Out of curiosity, is your IP address the same after you lose the connection and get it back again? You can check it at http://whatsmyip.net/

is it at the same time of day every time it happens? likely cause is that you have a docsis 2 band modem and it thinks it's being attacked by a buffer overflow attack and shutting down. the reason for this is they'll usually cap your speeds during peak hours, like they do for everyone, and they'll uncap it at certain times of night (9-10PM), and you'll get a huge surge of data. google your modem brand/model and see. if it's a docsis 3, you're fine and it's some other problem, if it's a 2 you need to call them back and get a replacement.

it happened to me like that, called charter 11 times over the course of two weeks before someone asked about the timing. there's no way for them to diagnose the issue because everything IS working fine, until it's not.

So I called up Charter and they told me I should buy an "amplifier" that should fix the problem. ... when he came back he asked what time would be best for the tech to come out and install it.
Before I call back and cancel, I'd like to know if this will actually help of if they're just trying to milk me for extra money?

Two methods exist to solve problems. Identify the problem; then fix it. Or shotgun - keep installing good parts until something works. Latter is a classic symptom of one who did not learn how to solve problems; therefore resorts to shotgunning (ie the amplifier). Graduates of military academies are taught engineering regardless of their major. The military needs people who can solve a problem. They do not want 'shotgunning'. Instead, hard facts (numbers) identifies a problem long before fixing it.

Numbers exist that define your failure. Even when the internet is working, numbers still identify a defect. Only then can a problem be solved the first time.

dB numbers are usually read from a server inside the modem. Better techs also carry a 'meter' to measure signal dBs.

A low dB signal strength or 'signal to noise' ratio is benchmark to be solved. Regardless of whether the internet is working or not. Numbers are critical. A problem is not solved until numbers say it is solved.

For example, a wire can be broken. A gap is small enough that internet signals still cross it. That gap gets bigger when wires get colder. Just one of maybe 100 possible reasons for your symptoms. The amplifier would only cure symptoms because a tech did not identify the broken wire.

Any tech that only says "It is fixed" is assuming you are naive. A responsible tech can say, for example, what the dBs were before he did anything. What he did. And what the new dBs now are. Of course, you have no idea what those numbers mean. But then post them. The fewer who actually know this stuff can then provide assistance. Or show you how to get better service from every service tech every time. Without numbers, a reply can only be 'try this' or 'maybe it is that'. Also called wild speculation or shotgunning. Numbers mean problems are solved the first time.

A tech can show you how read those numbers from the modem. Then you are empowered. Only then do you know whether customer support is pulling your chain or truly providing answers.

Currently, nobody can constructively answer your question because the all so important dB numbers have not been provided. You should know, when he leaves, that he shotgunned or solved problems as even taught to military academy graduates.